KABUL, Afghanistan — In a bid to fend off the threat of a nationwide financial crisis, the Afghan government scrambled to shore up Afghanistan’s largest bank on Saturday after lines of frantic depositors mobbed the bank for a third day.

The efforts, which an Afghan official said could include the injection of Afghan government funds into the privately owned Kabul Bank, are meant to head off the run on the bank by its customers, who have withdrawn more than $200 million in the past few days amid fears of a wider economic collapse.

Officials said the Afghan government had not decided whether it needed to bail out the bank. But the Afghan Central Bank has pulled in funds from abroad, including $300 million that had been held in the United States Federal Reserve Bank, to have money on hand to guarantee the bank’s liquidity, American officials said.

A small team of advisers from the United States Treasury Department was in Kabul providing technical assistance, but American officials said no United States funds would be involved in the effort to rescue the bank.

The panic began last week when the Central Bank ousted the bank’s chairman and the chief executive officer, after discovering that the bank had lent hundreds of millions of dollars to allies of President Hamid Karzai and poured money into risky real estate investments in Dubai.

The crisis threatened to undermine confidence in Afghanistan’s fledgling financial system, which was built under American guidance after the collapse of the Taliban government in 2001. Among the clients of the bank is the government, which pays the salaries of about 250,000 public employees through the bank, including those of security officials and the military.

The bank, whose major shareholders include a brother of Mr. Karzai and a brother of the first vice president, helped finance the president’s election campaign last year and lent luxury apartments in Dubai rent-free to well-placed officials. Those connections helped shield the bank from scrutiny, officials said.

The Afghan government has since appointed a chief financial officer of the Central Bank to run the Kabul Bank, transferred $100 million to the bank to ensure it could pay salaries of government employees and promised to guarantee investors’ deposits.

An American official described those moves, as well as the withdrawal of Afghan reserves from the United States and other central banks, as prudent steps a bank regulator should take in such a crisis.

But on Saturday they appeared to have done little to stem the panic. Thousands of nervous depositors were lined up outside the bank’s central branch in Kabul by 6 a.m. to withdraw their savings. Hundreds of men pushed and shoved their way to the front, while others waited behind them for hours in the sauna-like swelter of the lobby, making it impossible to discern where the lines ended and began.

But the teller drawers were largely empty and most customers left empty-handed. “What should I give you when I have nothing to give?” a teller told one agitated customer.

Similar scenes were reported at branches in other cities.

Top officials at Kabul Bank and a senior leader at the Central Bank declined to comment on the details of the rescue efforts, which were still being negotiated Saturday. However, a manager at the Central Bank and a senior American official confirmed that there would be what the American official called an “intervention.”

The United States is advising the Afghan government on how to manage the crisis, but is not contributing any American money, officials said.

“This is an Afghan issue,” Deputy Treasury Secretary Neal Wolin said in a statement. “While we are providing technical assistance to the Afghan government, no American taxpayer funds will be used to support Kabul Bank."

The official at the Afghan Central Bank, who, like others involved in the deliberations, requested anonymity, said that the bank’s risk management department was preparing to take over operations at Kabul Bank, and that Kabul’s existing management would be purged.

A major shareholder in the bank, Mahmoud Karzai, the brother of the Afghan president, said Saturday that government assistance would be unnecessary considering that the bank still retained half of its assets, which officials say are about $2 billion. He said the government “will absolutely guarantee” the salaries of public servants and was transferring money to Kabul Bank each day.

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One of the customers waiting for his money at Kabul Bank on Saturday was a Central Bank employee, who said that the government might prevent a long-term crisis but that it did little to ease his short-term fears.

“I don’t want to lose my money,” said the man, who refused to give his name because of his position at the Central Bank.

Officials at Kabul Bank said they had not yet calculated how much money customers withdrew on Saturday, but that they believed that the figure was less than in previous days. On Thursday, one of the bank’s principal owners said depositors had withdrawn $180 million in the previous two days.

But according to a bank employee distributing tickets for places in line to bank patrons, the crowds on Saturday were higher than ever. By 1 p.m., nearly 2,000 people were waiting in line.

Mahmoud Siakal, a former deputy foreign minister, said the bank’s problems reflected deeper problems with the government and the financial system.

“What’s happening with Kabul Bank shows an advanced level of the weakening of rule of law since 2002,” he said. “We beg the world to invest here, and on the other hand, our own wealth is disappearing from the country. The fact that government is guaranteeing the bank won’t collapse — who gave them the right to inject all that money into Kabul Bank?”

Some economists argue that the crisis in the nation’s largest bank, if allowed to continue, could create a devastating ripple effect on other sectors of the economy. Others, however, say that because a vast majority of Afghanistan’s economy runs on cash and in the black market, the rest of the economy is largely immune from Kabul Bank’s woes.

The bank crisis is compounded by the coming arrival of Id al-Fitr, the Muslim holiday when Afghans punctuate the end of the holy month of Ramadan with lavish shopping sprees. Also, many other customers typically withdraw their monthly salaries at the start of each month.

The Afghanistan Banks Association, which represents of 17 commercial banks, called the situation “normal and controlled” because the public now understands that the government would not allow the bank to collapse.

Najibullah Amiri, the general secretary of the association, said the frantic customers at the bank were simply “illiterate people who hear the news and start withdrawing.” He said the bank had no liquidity issues.

At the bank’s main branch, an environmental engineer named Hamid disagreed. He had waited more than five hours to fill his straw vegetable sack with his entire savings: $100,000.

“I don’t trust my government,” he said, gripping the sack tightly. “They lie. I’m an old man, and I have enough experience in my life to know how this government is.”

10 Afghans Killed in Bombings

KABUL, Afghanistan — Ten Afghans, including four police officers, were killed Saturday in bombings in the cities of Kunduz and Kandahar, NATO and local government officials said.

In Kunduz, a remote-controlled bomb detonated atop a parked motorcycle, killing seven Afghans, including the four police officers, local officials said.

Correction: September 9, 2010

An article on Sunday about a deal to stabilize Afghanistan’s largest bank overstated, in some copies, the role of the United States in the effort. White House officials said the United States was providing technical assistance, not bailout money.

A version of this article appears in print on September 5, 2010, on Page A8 of the New York edition with the headline: Afghanistan Tries to Help Nation’s Biggest Bank as Panic Continues. Order Reprints|Today's Paper|Subscribe